Quite so - and the Romulans merely lied about Kirk violating that border. By "nowhere near" I didn't really wish to suggest that Kirk was charting cislunar space or surveying Klingon planets...

Obviously, after the failed first strike, the Romulans would want to retire to the RNZ or even all the way into Romulan space, so as to avoid being caught for the violation for nothing. But the Joker taking the ship back to the RNZ would mean taking them back to the danger zone, as the willingness of the Romulans to strike out of that zone was now established.